Lutessa Luthor grew up knowing that Lionel Luthor was her father and was raised by him but was disowned because she was not special. Despite being siblings, Tess was having a passionate affair with Clark Luthor and together planned to use the Lionel's Mirror box to escape to a new earth and make it their own. When Clark Kent was sent to this darker reality, Tess did not take long to realize that they were not the same person and helped Clark realize what happened.

After trying to get information about the Kryptonian device from Lionel's office, she was discovered by him and after a heated argument where Tess claimed that he never loved her, she was arrested by security for having slapped Lionel.